I am currently taking a beginners statistics course and in my current homework, I had to analyze sales figures of three different products in two environments (east coast and west coast) in a two-way ANOVA. The results give me a significant main effect for both independent variables (
p = 0.001 and
0.0001) as well as a significant interaction effect (
p = 0.011) with all effects being strong (all eta-squared are over 0.09, which is considered to be high).
However, when I create an interaction plot, I see that the lines for two items (2 & 3) are parallel.
Does that have any meaning or should I still consider the lines to be non-parallel (= a significant interaction effect exists)?